During his interview with President Trump, “Fox News Sunday” host Chris Wallace may have uttered four of the most important words in the long, jagged history of Trump TV interviews: “That’s not true, sir.”

Wallace was referring specifically to Trump’s false assertion that the United States has the lowest coronavirus mortality rate in the world — but it set a more general tone. Given how rare it is for Trump to be called out so plainly during a televised interview — let alone one on Fox — this simple statement acted like a brake on Trump, forcing the president to backtrack and defend himself.

He couldn’t.

The Sunday interview was widely praised for Wallace’s deftness in exposing Trump’s most bogus claims, such as the covid-19 death rate and his assertion that Democratic challenger Joe Biden had agreed to “abolish” police funding as part of an alliance with Bernie Sanders. Wallace not only said it wasn’t true, he showed it — when handed a document describing Biden and Sanders’s shared agenda, Trump couldn’t find any reference to a plank abolishing police funding. “This thing is many pages long,” the president muttered, before giving up.

That Wallace’s interview occurred on Fox — a network that Trump seems to regard as an extension of the White House — attests to the 72-year-old host’s independence from his employer. And it stood in stark contrast to the otherwise forgettable, fumbling or even downright fawning interviews with the president. ABC anchor David Muir, who in May landed the first non-Fox interview with Trump since the pandemic started, was hammered by critics — including inside his own network — for failing to challenge Trump’s blatant misinformation.

Wallace’s polite but firm questions and follow-ups suggested to a number of expert observers that he had cracked the code on interviewing Trump, a man who has spent decades outmaneuvering TV interviewers by evading questions, badgering the interviewer or laying down a fog of uncheckable boasts and outright lies.

An effective interview is not “a fight,” said veteran TV host Greta van Susteren, now at Voice of America, but a search for information that viewers didn’t have before. “It’s not a contest. It is about learning something new.”

Wallace wasn’t merely prepared with the facts — he knew how to deploy them, with the experience and instincts to guide him on when to challenge Trump and when to lay back. He didn’t seek an explosive confrontation with Trump, in the style of his late father, the famously combative “60 Minutes” correspondent Mike Wallace. Such “moments” create telegenic clips, said Soledad O’Brien, the former CNN host — but end up being as much about the interviewer as the subject.

In an interview that aired July 19, "Fox News Sunday" host Chris Wallace asked President Trump about the coronavirus, upcoming elections and civil unrest. (The Washington Post)

Instead, Wallace remained relatively aloof, picking his battles. “The president has verbal diarrhea. He lies constantly. If you’re not careful, you can get trapped in all the rabbit holes he creates,” said O’Brien, now an independent TV producer and host. Wallace avoided getting “drawn into the vortex of [Trump’s] crazy lies,” she said, adding that he let Trump hurt himself “by not interrupting the flow of the interview.”

But he also had two key advantages, she noted: a generous amount of time to talk with Trump, and the luxury of doing it on tape.

Live interviews — the predominant format for national TV news interviews — offer immediacy and a sense of drama. But they pose hurdles for real-time fact-checking, enabling a wily politician to dash off questionable statements barely impeded. And they are rarely more than a few minutes long, compelling an interviewer to move through questions quickly, limiting the opportunity for follow-ups.

“Fox News Sunday’s” format overcame both these limitations. Wallace’s encounter with Trump was recorded Friday and aired about 48 hours later. This gave Wallace and his producers time to insert context and fact checks into the interview. Wallace was able to note in a voice-over, for example, that the White House’s own figures didn’t support Trump’s assertions about the United States having “the lowest” covid-19 fatality rate.

And with 40 minutes of the president’s schedule devoted to him, Wallace had ample time to work through his questions and still linger on certain topics. “It doesn’t always serve the audience to do things live,” O’Brien said.

Fox News declined a request for an interview with Wallace about how he approaches interviews.

A veteran of three networks, Wallace is a leader on the news side of Fox, and he has the respect of the network’s executives, according to colleagues. He is based in Fox’s Washington bureau and occupies his own office “pod” where he and his team research and hash out the week’s show.

In between his weekly program — which is carried on Fox’s broadcast stations as well as the cable network itself — Wallace anchors major news events and is a staple of Fox News’s election coverage.

He joined Fox in 2003 from ABC News, following the 1996 trajectory of his former ABC colleague Brit Hume. Fox co-founder Roger Ailes saw both hires as coups that bolstered the news credentials of his fledgling creation. And especially since the departure of Shepard Smith last fall, Wallace’s reputation (along with that of anchor Bret Baier) as an independent willing to challenge Republican leaders has been key to Fox’s defense against charges of bias.

In recent months, Wallace has occasionally been at odds with some of his Fox News colleagues — most notably in September, following reports that an anonymous whistleblower had lodged a complaint against Trump for his effort to pressure Ukraine’s president to launch an investigation of Biden. After Fox News anchor Sandra Smith pointed out what she called “major inconsistencies,” including the lack of a “quid pro quo” in the whistleblower’s complaint, Wallace pushed back.

“What is clear from reading the complaint is that it is a serious allegation,” he said. “A lot of it has proven to be borne out already.” And, Wallace added: “To dismiss [the whistleblower] as a political hack seems to be an effort by the president’s defenders to make nothing out of something, and there is something here. . . . It’s not nothing. It’s something.”

Wallace also clashed with Fox News host Laura Ingraham in May 2019 after then-special counsel Robert S. Mueller III objected to Attorney General William P. Barr’s characterization of Mueller’s findings in his lengthy investigation of Trump.

Wallace said that Mueller made his comments to place a “spotlight” on Barr before Barr testified to Congress. Ingraham scoffed that Wallace “agrees with these other cable networks” that were in a “frenzy” over Barr. And then Wallace — without naming Ingraham — responded pointedly that “some opinion people who appear on this network” may have a “political agenda” to push, but that he was sticking with his own analysis.

Not all of Wallace’s competitors were so enamored of his Trump interview. One TV news host faulted Wallace for not zeroing in on the pandemic with detailed questions about the government’s failure to contain the virus. “It should have been a plea for action and a detailing of all the things [health officials] want him to do,” said the host, who spoke on the condition of anonymity because his network didn’t authorize an interview.

MSNBC host Lawrence O’Donnell noted on his show Monday that although Wallace did some “spectacular fact-checking,” he failed to call Trump on several other misstatements, such as his claim about progress on building the southern border wall. And Wallace never asked Trump about his inaction on intelligence reports that Russian operatives offered bounties to insurgents in Afghanistan to kill American soldiers stationed there.

“There is no greater dereliction of duty by an American commander in chief that we know about,” said O’Donnell. “But there was no time for that in the Fox interview . . . no time.”

Wallace, though, did ask Trump about the cognitive test he has frequently boasted about passing, creating another of the interview’s viral moments. Wallace pointed out that he, too, had taken it, and “it’s not the hardest test” — one question involved correctly identifying a picture of an elephant. Trump sputtered that the final few questions were much more challenging.

“Well, one of them was count back from 100 by seven,” Wallace noted, before helpfully offering, “Ninety-three. . . .”